The present invention relates to a gate valve. More particularly, the invention relates to a gate valve which comprises a plurality of flow paths extending between respective inlet and outlet ports and a gate member for controlling the flow of fluid through each of the flow paths.
The need to control the flow of fluid through multiple flow paths exists in many applications. One such application is a flow completion system for producing oil or gas from a subsea well. A typical horizontal-type flow completion system comprises a wellhead housing which is installed at the upper end of a well bore, a tubing spool which is connected to the top of the wellhead housing, and a tubing hanger which is suspended in the tubing spool. In addition to supporting at least one tubing string which extends into the well bore, the tubing hanger may also comprise several service and control conduits for communicating hydraulic control fluid or chemicals to corresponding devices or positions located in the well bore below the tubing hanger. These service and control conduits are connected to corresponding external service and control lines typically via radial penetrators which extend through the tubing spool and into the tubing hanger. In order to ensure that the service and control conduits do not permit well fluids to escape into the environment, each service and control conduit typically must include a closure member to seal off the service and control conduit when it is not in use.
In prior art flow completion systems, a poppet-type valve is usually installed in the end of each service and control conduit adjacent the radial penetrator to seal off the service and control conduit when it is disengaged from the radial penetrator. While this poppet-type valve is sufficient to provide a single barrier between the well bore and the environment through the service and control conduit, industry standards often require that such conduits include two barriers. Although a second barrier may be achieved by providing a second valve in each service and control conduit, such valves would each require a separate actuating mechanism comprising a separate set of control lines, and this would necessarily increases the cost and complexity of the flow completion system.
In accordance with the present invention, these and other disadvantages are overcome with a multiport gate valve assembly which comprises an elongated body having a longitudinal bore extending therethrough, a plurality of gates slidably disposed in the longitudinal bore across respective flow passages that each extend laterally through the body between corresponding inlet and outlet ports, and an actuator for moving the gates simultaneously between their respective open position, wherein an opening in each gate is aligned with its corresponding flow passage, and a closed position, wherein the opening is offset from its flow passage. Thus, the gate valve assembly of the present invention is capable of simultaneously controlling the flow of fluid through several different flow passages.
In a preferred embodiment of the invention, the body comprises first and second spaced apart entrance bores and the longitudinal bore extends substantially between the first and second entrance bores. In addition, the actuator comprises a first piston which is disposed in the longitudinal bore between the first entrance bore and the gates, a second piston which is disposed in the longitudinal bore between the second entrance bore and the gates, and a source of hydraulic fluid which is connected to each of the first and second entrance bores. Thus, application of hydraulic fluid to either the first or the second entrance bore will move the gates simultaneously between their respective open and closed positions.
In this manner, the multiport gate valve assembly of the present invention provides a simple and effective means for controlling the flow of fluid through a plurality of individual flow paths. When used in conjunction with a flow completion system, the inlet ports may be connected to the service and control conduits which extend through the tubing hanger and the exit ports may be connected to corresponding devices or positions located below the tubing hanger. Thus, the multiport gate valve assembly can provide a second barrier between the well bore and the environment through the service and control conduits without the need for individual valves in each conduit.
These and other objects and advantages of the present invention will be made apparent from the following detailed description, with reference to the accompanying drawings. In the drawings, the same reference numbers are used to denote similar components in the various embodiments.